The range of tolerances
listed below do not represent ASTM C90-02 in its entirety.
If you have questions regarding C90-02 specification
information not found below, please visit the NCMA
TEK, ASTM
link, or Contact Us.

Weight– Oven Dry

8” Block Weight

Lightweight

Less than 105 lbs. per
cubic ft.

(Less than 29.25 lbs.)

Medium Weight

At least 105 lbs. per
cubic ft. but less than 125 lbs. per cubic ft.

(At least 29.25 lbs.)
(Less than 34.83 lbs.)

Normal Weight

At least 125 lbs. per
cubic ft. or more

(34.83 lbs. or more)

Compressive Strength

(Average of 3 blocks)
Minimum of 1900 lbs. per square inch on the net area
No individual block may be less than 1700 lbs. per square
inch

NOTE: Former requirements for
moisture content have been eliminated from C90-02. All
former ASTM C90 “type” classifications for
moisture content i.e. “Type I Moisture Controlled
Units” and “Type II Nonmoisture Controlled
Units” have been eliminated from ASTM C90-02.